powerpc/86xx: Move PCI/PCIe address defines into common immap_86xx.h

Remove dupliacted setting of PCI/PCIe address and offsets in board
config.h.  Renamed CONFIG_SYS_PCI1/2_ADDR to CONFIG_SYS_PCI1/2ADDR on
MPC8641 boards since its really PCIE controllers and not PCI.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>